I'm trying to replace my exsisting faucets that has a separate hot and cold fixture. They have a nut on the spline and a lock nut up against the underside of the sink. I have sprayed WD-40 and can turn the nut about a half inch but it tightens up again no matter which way I turn it. This set-up was installed about six years ago. Do I have to replace the entire sink? ANy help out there? signed...TIGHT NUTS